It is well known to cover a metal wire with a thermoplastic resin. A PVC-covered or polyethylene-covered wire is widely used for a variety of purposes including, for example, conductors, wires, fences and general merchandise such as a hanger. Since vinyl chloride and polyethylene are lacking in toughness and weather resistance, it is necessary to cover the metal wire with a layer of at least 1 mm in thickness. It is well known that the film of polyethylene terephthalate polymer is tough. There is described in the specification of U.S. Pat. No. 3,829,545 a method comprising covering a metal wire with a film, 0.1 to 0.3 mm thick, of polyethylene terephthalate. However, thinner covering is desirable for various applications. For example, when it is intended to use the covered metal wire for motor windings, much thinner covering is strongly required to reduce the weight. Prior to the present invention, however, it has not been the practice to cover a metal wire with a thin thermoplastic resin film which is as thin as 10 to 80.mu..
It is an object of the present invention to provide a thermoplastic resin-covered metal wire in which the metal wire is closely covered with a resin film which is tough and thinner than those of conventional metal wires.